Submission #19837

#	Time	Username	Problem	Language	Result	Execution time	Memory
19837		yukariko	괄호 (kriii4_R)	C++14	0 / 100	7 ms	19300 KiB

R

#include <bits/stdc++.h>

using namespace std;

const int MOD = 1000000007;

int N, M;

long long cache[2000001];
char res[2000001];

long long solve(int pos)
{
	if(pos > 2 * N)
		return 0;
	if(pos == 2 * N)
	{
		puts(res);
		return 1;
	}

	long long& ans = cache[pos];
	//if(ans != -1)
	//	return ans;

	res[pos / 2] = '(';
	res[2 * N - (pos / 2) - 1] = ')';
	ans = (solve(pos + 2) * M) % MOD;
	res[pos / 2 + 1] = ')';
	res[2 * N - (pos / 2) - 2] = '(';
	ans = (ans + solve(pos + 4) * M) % MOD;
	return ans;
}


int main()
{
	memset(cache, -1, sizeof(cache));
	scanf("%d%d", &N, &M);

	cache[0] = M;
	cache[1] = M;
	for(int i=2; i <= N; i++)
		cache[i] = (cache[i-1] * 2 + cache[i-2] * 4 * (i - 1)) / (i + 1);

	printf("%lld\n", cache[N]);
	return 0;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 92